I poked some fun at the History Channel recently for their devotion to the Mayan calendar and their ominous programs in the run up to December 21, 2012. I wondered in my column what they would do to replace all those shows about the Mayan calendar, once it became obvious the world was not ending on December 21, 2012.

The answer has arrived. The History Channel has doubled down on Ancient Aliens. For those who have never heard this theory, it holds that in ancient times extra terrestrials came to the earth and intervened in human events. According to the theory, they imparted significant knowledge to given cultures, and in doing so helped advance human civilization.

Among the things ancient aliens are claimed to have played a role are the pyramids and the Sphinx in Egypt, the pyramids of Mexico and Central America, Stonehenge, and other such major constructions. These structures often appear to evidence significant knowledge and understanding of astronomy, time, and math - and those sometimes appear to be more advanced than we might expect of such cultures.

The movement of monoliths of great weight for great distances is one aspect of ancient construction which fuels ancient aliens theorists. The heads of Easter Island, for example, are the top of stone artifacts which are not just the heads, but entire stone bodies buried up to the head. From Mexico, to the British Isles, to Southeast Asia, to northern Africa, rocks weighing tens of thousands of pounds, or even hundreds of thousands of pounds, were moved great distances after having been cut from quarries. It boggles the mind imagining how ancient people with ancient tools and transportation were able to find, mine, cut, shape, move and erect these stone edifices.

The theory that ancient aliens intervened in human events is based in large part upon ancient texts which tell of heavenly visitors who intervene in earthly matters to shape the outcome of key points of civilization. Many of these ancient texts are considered holy sources by many who believe in them. The Bible is certainly among these.

The Old Testament contains stories which could be viewed as evidence of ancient aliens. The theorists maintain that Biblical stories of angels or other godly messengers could have been attempts to describe contacts from other worldly beings. We are told in Genesis that before the time of Noah, gods came down to earth and took human wives, producing offspring. We are told that visitors sent from God saved Lot and his family from the planned destruction of Sodom and Gomorrah. We read a story of a fiery chariot which came out of the sky, picked up a prophet, and flew away into the heavens.

In medieval art are many paintings which appear to show UFOs in the skies. The art sometimes has stories which were recorded at the time, describing in great detail aerial battles from flying aircraft, long before any such machines are known to have existed on earth.

I do not write to advocate for any of this, but because I think it is thought provoking and not impossible. I am dubious on much of the "evidence" used to advance this theory, but I remain open minded as to whether any extra terrestrial has ever influenced human existence.